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 * Copyright 2002-2022 the original author or authors.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      https://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
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 *除非符合许可证，否则不得使用此文件。
 *您可以在以下地址获取许可证副本：
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package org.springframework.beans.factory.support;

import org.springframework.beans.BeanUtils;
import org.springframework.beans.factory.config.BeanDefinitionHolder;
import org.springframework.beans.factory.config.DependencyDescriptor;
import org.springframework.lang.Nullable;

/**
 * Strategy interface for determining whether a specific bean definition
 * qualifies as an autowire candidate for a specific dependency.
 *
 * @author Juergen Hoeller
 * @author Mark Fisher
 * @since 2.5
 */
/**
 *用于确定特定bean定义
 *符合特定依赖项的自动连线候选项。
 *
 *@作者Juergen Hoeller
 *@作者Mark Fisher
 *@自2.5
 */
public interface AutowireCandidateResolver {

	/**
	 * Determine whether the given bean definition qualifies as an
	 * autowire candidate for the given dependency.
	 * <p>The default implementation checks
	 * {@link org.springframework.beans.factory.config.BeanDefinition#isAutowireCandidate()}.
	 * @param bdHolder the bean definition including bean name and aliases
	 * @param descriptor the descriptor for the target method parameter or field
	 * @return whether the bean definition qualifies as autowire candidate
	 * @see org.springframework.beans.factory.config.BeanDefinition#isAutowireCandidate()
	 */
	/**
	 *确定给定的bean定义是否符合
	 *给定依赖项的autowire候选项。
	 *＜p＞默认实现检查
	 *{@link.org.springframework.beans.factory.config.BeanDefinition#isAutowireCandidate（）}。
	 *@param bdHolder包含bean名称和别名的bean定义
	 *@param descriptor目标方法参数或字段的描述符
	 *@return bean定义是否符合autowire候选
	 *@see org.springframework.beans.factory.config.BeanDefinition#isAutowireCandidate（）
	 */
	default boolean isAutowireCandidate(BeanDefinitionHolder bdHolder, DependencyDescriptor descriptor) {
		return bdHolder.getBeanDefinition().isAutowireCandidate();
	}

	/**
	 * Determine whether the given descriptor is effectively required.
	 * <p>The default implementation checks {@link DependencyDescriptor#isRequired()}.
	 * @param descriptor the descriptor for the target method parameter or field
	 * @return whether the descriptor is marked as required or possibly indicating
	 * non-required status some other way (e.g. through a parameter annotation)
	 * @since 5.0
	 * @see DependencyDescriptor#isRequired()
	 */
	/**
	 *确定是否有效地需要给定的描述符。
	 *＜p＞默认实现检查｛@link DependencyDescriptor#isRequired（）｝。
	 *@param descriptor目标方法参数或字段的描述符
	 *@return描述符是否标记为必需或可能指示
	 *其他方式（例如通过参数注释）的非必需状态
	 *@自5.0
	 *@参见DependencyDescriptor#isRequired（）
	 */
	default boolean isRequired(DependencyDescriptor descriptor) {
		return descriptor.isRequired();
	}

	/**
	 * Determine whether the given descriptor declares a qualifier beyond the type
	 * (typically - but not necessarily - a specific kind of annotation).
	 * <p>The default implementation returns {@code false}.
	 * @param descriptor the descriptor for the target method parameter or field
	 * @return whether the descriptor declares a qualifier, narrowing the candidate
	 * status beyond the type match
	 * @since 5.1
	 * @see org.springframework.beans.factory.annotation.QualifierAnnotationAutowireCandidateResolver#hasQualifier
	 */
	/**
	 *确定给定的描述符是否声明了超出类型的限定符
	 *（通常-但不一定-一种特定的注释）。
	 *＜p＞默认实现返回｛@code false｝。
	 *@param descriptor目标方法参数或字段的描述符
	 *@return描述符是否声明限定符，缩小候选项
	 *状态超出类型匹配
	 *@自5.1
	 *@see org.springframework.beans.factory.annotation.QualifierAnnotationAutowireCandidateResolver#hasQualifier
	 */
	default boolean hasQualifier(DependencyDescriptor descriptor) {
		return false;
	}

	/**
	 * Determine whether a default value is suggested for the given dependency.
	 * <p>The default implementation simply returns {@code null}.
	 * @param descriptor the descriptor for the target method parameter or field
	 * @return the value suggested (typically an expression String),
	 * or {@code null} if none found
	 * @since 3.0
	 */
	/**
	 *确定是否为给定依赖项建议默认值。
	 *＜p＞默认实现只返回｛@code null｝。
	 *@param descriptor目标方法参数或字段的描述符
	 *@return建议的值（通常是表达式String），
	 *或｛@code null｝（如果未找到）
	 *@自3.0
	 */
	@Nullable
	default Object getSuggestedValue(DependencyDescriptor descriptor) {
		return null;
	}

	/**
	 * Build a proxy for lazy resolution of the actual dependency target,
	 * if demanded by the injection point.
	 * <p>The default implementation simply returns {@code null}.
	 * @param descriptor the descriptor for the target method parameter or field
	 * @param beanName the name of the bean that contains the injection point
	 * @return the lazy resolution proxy for the actual dependency target,
	 * or {@code null} if straight resolution is to be performed
	 * @since 4.0
	 */
	/**
	 *为实际依赖目标的延迟解析构建代理，
	 *如果注射点需要。
	 *＜p＞默认实现只返回｛@code null｝。
	 *@param descriptor目标方法参数或字段的描述符
	 *@param beanName包含注入点的bean的名称
	 *@返回实际依赖目标的懒解析代理，
	 *或｛@code null｝（如果要执行直接解析）
	 *@自4.0
	 */
	@Nullable
	default Object getLazyResolutionProxyIfNecessary(DependencyDescriptor descriptor, @Nullable String beanName) {
		return null;
	}

	/**
	 * Determine the proxy class for lazy resolution of the dependency target,
	 * if demanded by the injection point.
	 * <p>The default implementation simply returns {@code null}.
	 * @param descriptor the descriptor for the target method parameter or field
	 * @param beanName the name of the bean that contains the injection point
	 * @return the lazy resolution proxy class for the dependency target, if any
	 * @since 6.0
	 */
	/**
	 *确定依赖目标的延迟解析的代理类，
	 *如果注射点需要。
	 *＜p＞默认实现只返回｛@code null｝。
	 *@param descriptor目标方法参数或字段的描述符
	 *@param beanName包含注入点的bean的名称
	 *@返回依赖目标的惰性解析代理类（如果有）
	 *@自6.0起
	 */
	@Nullable
	default Class<?> getLazyResolutionProxyClass(DependencyDescriptor descriptor, @Nullable String beanName) {
		return null;
	}

	/**
	 * Return a clone of this resolver instance if necessary, retaining its local
	 * configuration and allowing for the cloned instance to get associated with
	 * a new bean factory, or this original instance if there is no such state.
	 * <p>The default implementation creates a separate instance via the default
	 * class constructor, assuming no specific configuration state to copy.
	 * Subclasses may override this with custom configuration state handling
	 * or with standard {@link Cloneable} support (as implemented by Spring's
	 * own configurable {@code AutowireCandidateResolver} variants), or simply
	 * return {@code this} (as in {@link SimpleAutowireCandidateResolver}).
	 * @since 5.2.7
	 * @see GenericTypeAwareAutowireCandidateResolver#cloneIfNecessary()
	 * @see DefaultListableBeanFactory#copyConfigurationFrom
	 */
	/**
	 *如有必要，返回此解析器实例的克隆，保留其本地
	 *配置并允许克隆的实例与
	 *一个新的bean工厂，或者这个原始实例（如果没有这样的状态）。
	 *＜p＞默认实现通过默认值创建单独的实例
	 *类构造函数，假定没有要复制的特定配置状态。
	 *子类可以通过自定义配置状态处理来覆盖此项
	 *或具有标准{@link Cloneable}支持（由Spring的
	 *自己的可配置｛@code AutowireCandidateResolver｝变量），或者简单地
	 *返回｛@code this｝（如在｛@link SimpleAutowireCandidateResolver｝中）。
	 *@自5.2.7起
	 *@参见GenericTypeAwareAutowireCandidateResolver#cloneIfNecessary（）
	 *@参见DefaultListableBeanFactory#copyConfigurationFrom
	 */
	default AutowireCandidateResolver cloneIfNecessary() {
		return BeanUtils.instantiateClass(getClass());
	}

}
